| A | B |
|---|
| Richter scale | Scale measure the actual width of the seismograph to indicate the intensity of an earthquake. 1-10, each number is 10x greater than the previous #. |
| Earthquake | Movement of the earth along faults and plate boundaries. |
| Seismic waves | Vibrations that that travel through the earth carrying the energy released during an earthquake. |
| P Waves | Primary earthquake waves. Travel back and forth in one direction. Faster travelling waves. Goes through solids and Liquids |
| S Waves | A type of seismic wave that moves the ground side to side or up and down. Slower moving waves but more destructive. Does not travel thru liquids. |
| Fault | A break or crack along which rock moves in the earth's crust. |
| Stresses | Compression, tension and shearing of plates. |
| Normal Fault | A type of fault where the hanging wall slides below the footwall. Caused by Tension |
| Reverse Fault | A type of fault where the hanging wall rises above the footwall. Caused by compression. |
| Strike slip Fault | A type of fault where rocks slide past each other. San Andreas is an example. |
| Surface waves | A type of seismic wave that forms when P and S waves reach the surface of the earth. |
| Epicenter | Point on the earth directly above the source of the earthqauke |
| Mercalli Scale | An earthquake scale that rates them according to the level of damage done at a given place and their intensity-Roman Numeral I-XII |
| Moment magnitude | Introduced in 1979 measures the total amount of energy released during the earthquake |
| Intensity | measure the amount of shaking |
| Magnitude | is the amount of energy released. |
| Hypocenter | Or Focus is the point under the surface where the earthquake originates. |
| Liquefaction | The soil turns soft and liquifies during an earthquake. |
